Posted
by
timothyon Tuesday February 28, 2012 @01:56PM
from the ask-the-master dept.

New submitter Stowie101 writes "British master engineer Ian Shepherd is ripping Apple's Mastered for iTunes service, saying it is pure marketing hype and isn't different than a standard AAC file in iTunes. Shepherd compared three digital music files, including a Red Hot Chili Peppers song downloaded in the Mastered for iTunes format with a CD version of the same song, and said there were no differences. Apple or someone else needs to step it up here and offer some true 'CD quality downloads.'"

Then again...maybe not...the compression wars are killing me. I just got the latest "remastered" edition of the Stones Some Girls album...I have tried twice to listen to it on my home stereo, and it just is painful to the ears. For some reason, however, the 2nd disc that came with it of outtakes/unreleased stuff..sounded pretty good.

Why they have to ruin a good album....grrr....I wish the cheap ipod earbud had never been invented. Too much crap being mixed for those, instead of quality listening environments....

I can't speak for the RHCP tracks, but I downloaded a dozen or so tracks I already have on CD and exist as both FLAC and LAME MP3s on my computer on the day of the announcement to see what the difference is. I could immediately tell a difference with the Master for iTunes tracks, better or worse, I'm not sure yet. They are easy to pick out in A/B testing, the most glaring difference is in the mid-bass area 80-120hz is noticeably boosted in the rock tracks I downloaded.

I'm not an iTunes fan at all, nor an audiophile, but I believe the idea of remastering for itunes is not to put back lost data, but for account for it.

This is me making it up: "Oh, it looks like AAC will reduce sounds in the 18 KHz range, but that makes the bass too powerful and affects the voice. I can reduce the bass a bit and up the voice frequencies to compensate and now it sounds better than pure AAC applied blindly."

"Mastered for iTunes" is just a set of guidelines that ensure that the resulting AAC file is the highest quality possible when encoded directly from a 24-bit master. It's higher quality then most FLACs because they are usually 16-bit, whereas AAC is essentially 24-bit when the source material is 24-bit. In essence, compressing 24-bit audio to 256kbps AAC sounds better then going to 16-bit uncompressed audio.

If you're going to go FLAC, at least make sure that you're getting 24-bit.

Somewhere in between. From the fine article he reversed the phase on one and added it and listened to what fell out, which wasn't much. Essentially a lot of complicated analog foolishness to figure out the delta between two files. Would seem you could do a lot simpler version of this digitally, decode both into raw / wav files, then calculate the diff between the two raw files.

Every lossless decoder drops the phase information, because the ear cannot hear it. That's half the data dropped without any loss in sound quality. So if you convert AAC back to uncompressed, the individual values have no similarity with the original at all.

Imagine recording the same music with microphones that are one meter apart. The sound is the same to the human ear. But one meter is about 3 milliseconds, so any sound at 600 Hz will have exactly the opposite amplitude on both microphones.

So what he first had to do is take the CD and the encoded file, and then add the phase data from the CD back. Absolutely necessary for any meaningful results.

While I agree that its all bunk, I would be interested in knowing if the two files where bit for bit the same or just sound the same to the listener?

The summary above is sort of confusing. You have to RTFA

Quote TFA

The British mastering engineer Ian Shepherd goes deeper in his analysis of Mastered for iTunes by using a music engineering tool called a null test. Shepherd explains this procedure as a method of reversing the phase of a song’s waveform so that after a song’s waveforms and volumes are matched in software a mixing engineer can play them back to see if the song’s out of phase waveform cancels or nulls out the normal version of the song.

After his comparison of the three digital music files, Shepherd says there was a sonic difference between the Mastered for iTunes waveform and the CD waveform. He says the Mastered for iTunes and AAC-encoded files didn’t reveal any differences,

So the the answer is that there is no reason to believe the files were bit-for-bit the same (that would be impossible in any encoding), and they didn't necessarily sound the same either. He had to use digital methods to discover the differences.

And he was comparing the standard AAC against the CD and the Mastered for Itunes against the CD, and the standard AAC against the MFI encoding.

And in both cases there were differences between the AAC versions and the CD, but none between the two encoded versions.

He did not say he could hear the differences without technical means. Usually if the engineer has to go to these lengths to discern any differences it means he couldn't tell them by ear alone.

And if he can't tell by ear alone, then A) it doesn't matter, or B) he has geezer ears."Mastering Engineer" status is a short lived career. By the time you get there, your ears are no longer qualified for the work. Technical means to the rescue.

"Digital douchery" (otherwise known as "analysis") is accurate, where as your ears are imperfect perceptions interpreted by your imperfect brain. If you want to deliver useful information to people, you do it digitally and present the results.

So take your hipster nonsense and piss off. Any real audiophile would care about what's accurate and useful.

On of my favourite experiments one of the high-end HiFi magazines did a very long time ago, when CD was new, was to let a group of 'golden ears' audiophiles double blind test CD vs LP. And most of them could reliably distinguish between and prefer LP sound over CD in double blind test (which is good, a lot of people who are hellbent sure they know a difference will fail double blind testing). So far so good. Then they tested with CD-Rs recorded with LP as source.. Now they could no longer tell the difference, and thought the CD-Rs sounded just as good as LP. All that "warm, rich, musical, analogue" sound carried over to the CD-Rs, as they are distortion characteristics of LP playback. It is ok to prefer the sound, but it has nothing to do with CD vs LP or analogue vs digital (and digital is fully capable of reproducing it too if you want).